Linda Norgrove was killed by her captors, officials say, after U.S. special forces tried to free her. Elsewhere, four Italian troops are killed in an insurgent attack.

Reporting from Kabul, Afghanistan, and New Delhi — A British aid worker was killed by her captors after a failed rescue attempt by NATO forces in eastern Afghanistan, the British government said Saturday.

Linda Norgrove, 36, was taken hostage along with three of her Afghan co-workers in an ambush two weeks ago while visiting a project in Kunar province along the border with Pakistan. Her colleagues had already been released.

The British government gave few details on the Friday night rescue attempt, a former United Nations worker who headed a $150-million project attempting to strengthen local economies for the U.S. aid group Development Alternatives Inc.

NATO allies received a tip on Norgrove's whereabouts, and a decision was reportedly reached that her best chance, given the danger she faced, was to send in U.S. special forces.

"Responsibility for this tragic outcome rests squarely with the hostage-takers," British Foreign Secretary William Hague said in a statement. "From the moment they took her, her life was under grave threat."

Eight foreign medical workers and two Afghans were killed in August by unidentified gunmen in the nation's remote northeast, and two French journalists seized in December are still missing.

In another incident Saturday, four Italian troops in the International Security Assistance Force, led by the North Atlantic Treaty Organization, were killed in an insurgent ambush in western Afghanistan, Italy's Defense Ministry said.

Gen. Faqir Askar, the police chief of Farah province, said the logistical convoy was returning to its base there when the attack took place.

The latest violence comes as thousands of U.S. troops try to drive insurgents out of areas in and around the city of Kandahar, a major stronghold of the hard-line Taliban.

Afghan President Hamid Karzai visited the southern city on Saturday with U.S. Ambassador Karl Eikenberry and Gen. David H. Petraeus, the commander of U.S. and NATO forces, hoping to gain the support of hundreds of tribal elders in the region.

"I ask you to help cooperate with the government. We have brought security for you people," Karzai reportedly told the elders. "Try to keep it stable and try to tell those elders who have left their villages for the cities to come back."

The Kandahar offensive comes at an important time for President Obama in the lead-up to November midterm elections and a year-end review of the Afghanistan war strategy.

mark.magnier@latimes.com

Special correspondent Yaqoubi reported from Kabul and Times staff writer Magnier from New Delhi.